In the fast growing consumer electronic product market, there is increasing competition not only in product functionality but also in product reliability performance. For hand held electronic gadgets, the impact proof requirement is becoming more and more stringent. It is not unusual now to require a hand held device like a mobile phone to survive the impact from a 5000 gram weight and/or a free drop from a height of 1.5 meters to a steel plate, a process that can be repeated up to 10 times during a test.
One such electronic device, a backplateless silicon microphone, was disclosed by Wang et al. in Altus patent application AL04-001 and features a movable diaphragm which is supported at its edges, corners, or center by mechanical springs that are anchored to a conductive substrate through rigid pads. However, the mechanical springs may be broken in this configuration if there is a large movement in the suspended diaphragm resulting from an impact. Thus, it is necessary to improve the design of such a structure to incorporate features that will improve the durability of the device. The present invention addresses the need to enhance the impact stability of a backplateless silicon microphone.